Warn user if map is not supported

[crschnick]

In case the map is not supported (for whatever reason), we can show this information to the user on the front page already. We can check basic webgl requirements on the landing page, that doesn't require any resources.

[crschnick]

This could also included to check whether webgl2 is even supported

[nickbabcock]

webgl2 check already exists

pdx-tools/src/app/src/components/landing/BrowserCheck.tsx

Lines 12 to 14 in 49d0bdf

	if (!gl) {
	setWarnings((x) => [...x, "WebGL2 not available"]);
	} else if (maxTextureSize < requiredSize) {

[crschnick]

Add the context option failIfMajorPerformanceCaveat to this as well

[nickbabcock]

Done in af4cdbe

[crschnick]

We should also check if the amount of supported texture units in the fragment shader is >= 16